Biol_1202_2009_ex._3_review_questions_answered

Biol_1202_2009_ex._3_review_questions_answered - 1Biology...

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1Biology 1202 Review Questions for Third Exam Fall, 2009 Chapter 36 and 38 Vocabulary : proton pump, co-transport, turgor pressure, water potential, back pressure, solute pressure, mycorrhizae, endodermis, root pressure, transpirational pull, bisexual vs. unisexual flowers, incomplete flowers, pericarp, transgenic plants. 1. Understand how proton pumps and co-transport are important for movement of molecules and ions across plant cell membranes. Proton pumps actively transport H + out, anions and solutes in. 2. Understand what water potential and turgor pressure mean. Why do water molecules flow to more negative water potentials? How is back pressure and solute pressure involved? Be able to predict water flow based on Wp and Ws. Because evaporation at leaves creates transpirational pull which draws water up. Be able to use the equation given in class in an example. 3.What is guttation? Explain how water potential difference drives water flow from roots, up the trunk, and into and out of leaves. Be familiar with the general values of water potential involved. Guttation is dew when increased root solute concentration at night draws in so much water that it forms drops on the leaves. Water potential becomes more negative as you move up the trunk, resulting in water flowing from roots to the trunk and leaves. 4.How are guard cells and stomata involved in regulating the movement of gases and water in and out of leaves? What molecular mechanism causes stomata to open or close? Know guard cells open when turgid (due to inflow of K + which draws water in and makes cells turgid). This allows carbon dioxide in and oxygen out. Guard cells also open when carbon dioxide level gets to low within leaves. 5. What two mechanisms are involved in transport of sugars from leaves to roots? Hydrostatic flow down sieve tube elements and solute co-transport across phloem cell membranes (review figure in book) 6.Describe the series of steps that occur as sperm fertilize the ovule in the plant ovary. What is the endosperm and why is it important? What develops into the seed? The fruit? Male gametogenesis (formation of pollen), growth of pollen tube, fertilization, formation of fruit, seed dispersal. 7. Give an example of a plant variety produced by crossing, artificial selection and genetic engineering. What are the pluses and minuses of genetically engineered (transgenic) plants? Corn and wheat are the result of crosses of natural plants and artificial selection over thousands of years. Now we can rapidly genetically engineer plants to give them disease or pest resistance. But what happens if genes spread to closely related weeds, or if beneficial insects are affected? Chapters 33 and 34 Vocabulary : radial vs. bilateral symmetry, acoelomate vs. pseudocoelomate vs. coelomate, protostome vs. deuterostome, enterocoelous vs. schizocoelous, lophophore,
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This note was uploaded on 05/13/2010 for the course BIOL 1202 taught by Professor Gregg during the Spring '08 term at LSU.

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Biol_1202_2009_ex._3_review_questions_answered - 1Biology...

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